Obesity and Metabolic Syndrome Affects the Cholinergic Transmission and Cognitive Functions

Worldwide, at least 2.8 million people die each year as a result of being overweight or obese, that causes about 35.8 million (2.3%) of global Disability-Adjusted Life Year (DALYs). Obesity leads to metabolic syndrome, a pathological condition characterized by adverse metabolic effects on blood pressure, cholesterol, triglycerides and insulin resistance. Population-based investigations have suggested that obesity and metabolic syndrome may be associated with poorer cognitive performance and could be considered a possible risk factor for vascular Dementia and Alzheimer's Disease. Cognitive decline consists in an alteration in cognitive performance from a premorbid, baseline level. A number of pharmacological studies using acetylcholinesterase and cholinesterase inhibitors provides the role of the cholinergic system on cognitive functions. The common goal of these therapeutic strategies was to induce an increase of the acetylcholine concentrations in the synaptic space, prolonging and improving the binding of the acetylcholine with its own receptors. This review focuses the correlation between brain cholinergic system alterations and high-fat diet, detailing the involvement of cholinergic system in inflammatory processes related to metabolic syndrome and obesity, which may lead to cognitive decline.